This invention relates to a technique for manufacturing a semiconductor device and, in particular, to a technique for manufacturing a relatively low cost semiconductor device with improved seal properties in a CSP (Chip Size Package).
This invention is the result of the inventor""s own research of which a summary follows.
A CSP is a thin, compact semiconductor device of chip size, and it is often used in printed circuit boards built into portable electronic devices.
The general structure of a CSP comprises a thin film wiring substrate on which are mounted bump electrodes which are external terminals, leads electrically connected to electrode pads of a semiconductor chip, an elastomer (elastic structure) arranged between the semiconductor chip and the thin film wiring substrate and formed in approximately the same size as the thin film wiring substrate, and sealing parts which seal the electrode pads and the leads of the thin film wiring substrate connected to it.
Structures of CSPs studied by the inventor for comparison purposes are described, for example, in xe2x80x9cNikkei Microdevicesxe2x80x9d Apr. 1, 1997, No. 142, pp. 44-53, published by Nikkei BP Co. on Apr. 1, 1997, and, in particular, the next generation CSP structure (comparison examples) described in FIG. 6, on page 48 thereof. This CSP comprises a semiconductor chip having electrode pads formed on its main surface, bump electrodes which are external terminals over the main surface of the semiconductor chip, and a contour ring outside the semiconductor chip.
However, in a CSP having the aforesaid general structure according to the prior art, a sealing resin easily flows onto the sides of the semiconductor chip. This impairs the precision of the contour size of the CSP so that, in some cases, it could not be inserted in its socket.
In other words, a problem arises in that the contour shape of the CSP does not remain fixed.
If the amount of sealing resin is reduced in an attempt to solve this problem, the leads of the thin film wiring substrate may be exposed. The sealing properties of the sealing parts are then inadequate, and humidity resistance is not so reliable as a result.
In this comparison CSP of the prior art, if the contour ring is made a separate structure, manufacturing costs increase.
In a CSP having the usual structure, during solder reflow in forming the bump electrodes, the internal pressure rises due to expansion of moisture and gas in the elastomer, and as a result, the seal part is destroyed causing a xe2x80x9cpopcornxe2x80x9d phenomenon.
It is therefore an object of this invention to provide a chip size semiconductor device of lower cost and improved sealing properties, and a method of manufacturing such a device.
It is a further object of this invention to provide a semiconductor device and manufacturing method which prevents occurrence of this popcorn phenomenon.
This and other features of the invention will become clear from the following description and attached drawings.
The following is a simple description of the main points of a typical example of the present invention.
The semiconductor device of this invention is a chip size package having connection terminals provided on the outer periphery of its main surface. The package comprises an elastic structure arranged on the main surface of the semiconductor chip leaving the connection terminals exposed, a thin film wiring substrate comprising a substrate body having wiring whereof one end is electrically connected to the aforesaid terminals via leads and the other ends are electrically connected to bump electrodes which are external terminals and comprising substrate protruding parts having openings which leave the connection terminals exposed and which protrude beyond the openings and the semiconductor chip, and sealing parts which seal the connection terminals of the semiconductor chip and seal the leads of the thin film wiring substrate, the substrate body and the substrate protruding parts of the thin film wiring substrate being formed in a one-piece construction.
As the substrate protruding parts are not separate from the substrate body but are formed together with it in a one-piece construction, the substrate protruding parts need not be formed from costly materials. As a result, the cost of manufacturing the semiconductor device is reduced.
The semiconductor device of this invention is a chip size structure having connection terminals provided on the outer periphery of its main surface. It comprises an elastic structure arranged on the main surface of the semiconductor chip comprising elastic protruding parts having openings which leave the connection terminals exposed, a thin film wiring substrate comprising a substrate body having wiring whereof one end is electrically connected to the aforesaid terminals via leads and the other ends are electrically connected to bump electrodes which are external terminals, and comprising substrate protruding parts having openings which leave the connection-terminals exposed and which protrude beyond the openings and the semiconductor chip, and sealing parts which seal the connection terminals of the semiconductor chip and seal the leads of the thin film wiring substrate, the substrate body and the substrate protruding parts of the thin film wiring substrate being formed in a one-piece construction, and the thin film wiring substrate and the elastic structure having substantially the same size.
The semiconductor device of this invention is a chip size structure having connection terminals provided on the outer periphery of its main surface, comprising an elastic structure arranged on the main surface of the semiconductor chip having parts exposed to the outside for exposing the connection terminals, a thin film wiring substrate comprising a substrate main body having wiring whereof one end is electrically connected to the aforesaid connection terminals via leads and the other ends are electrically connected to bump electrodes which are external terminals, and comprising openings so as to expose the aforesaid connection terminals, and sealing parts which seal the connection terminals of the semiconductor chip and seal the leads of the thin film wiring substrate.
A method of manufacturing a semiconductor device according to this invention comprises a step for preparing a thin film wiring substrate which is a chip size structure having connection terminals provided on the outer periphery of its main surface, comprising a substrate body with wiring, and comprising substrate protruding parts which protrude beyond openings in which leads are connected to this wiring and formed in a one-piece construction with the substrate body, a step for joining an elastic structure and the substrate body of the thin film wiring substrate, a step for joining the main surface of the semiconductor chip and the elastic structure so as to expose the connection terminals of the semiconductor chip in the openings of the thin film wiring substrate, a step for electrically connecting the connection terminals of the semiconductor chip and the corresponding leads of the thin film wiring substrate, a step for sealing the connection terminals of the semiconductor chip and the leads of the thin film wiring substrate using a sealing resin comprising a low silica material so as to form sealing parts, a step for electrically connecting the wiring of the substrate body so as to form bump electrodes, and a step for simultaneously cutting the substrate protruding parts and sealing parts formed therein to a desired contour size.
A method of manufacturing a semiconductor device according to this invention comprises a step for preparing a thin film wiring substrate which is a chip size structure having connection terminals provided on the outer periphery of its main surface, comprising a substrate main body having wiring joined to an elastic structure and openings in which leads are connected to the wiring, wherein the substrate body is supported in a substrate frame by supporting parts of the elastic structure, a step for joining the main surface of the semiconductor chip and the elastic structure so as to leave the connection terminals of the semiconductor chip exposed in the openings of the thin film wiring substrate, a step for electrically connecting the connection terminals of the semiconductor chip and the corresponding leads of the thin film wiring substrate, a step for resin sealing the connection terminals of the semiconductor chip and the leads of the thin film wiring substrate so as to form sealing parts, a step for electrically connecting the wiring of the substrate body so as to form bump electrodes, a step for cutting the supporting part of the elastic structure so as to separate the substrate body from the substrate frame, and a step for exposing the exposed parts of the elastic structure.